The present invention relates to a structural testing device, and more particularly to a load controlled bending moment testing device which applies a constant moment along an elongated member.
Conventional structural testing is often performed with a three-point or four-point testing device as illustrated in FIG. 1A. Performing such structural tests on elongated members may be complicated as the elongated member tends to buckle at the discrete location of load application. In the case of thin hollow-walled shaft members, the concentrated shear loads (FIG. 1B) from such point bending testing may also cause local damage while generally under predicting the actual strength of the shaft.
Additionally, conventional point testing does not apply a constant bending moment along the entire length of the elongated member. Should the testing be structured as proof testing to eliminate flawed members, such testing may not eliminate all flawed members since a length ramped portion in FIG. 1C of the elongated member may not be subjected to the desired proof bending stress (FIG. 1C).
Accordingly, it is desirable to provide a structural testing device which determines nominal strength of an elongated member through application of a constant moment along the length of the elongated member without application of concentrated shear loads directly to the member.